Writing instrument



FIG. 1 is a front, right perspective view of a writing instrument showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a right side elevational view thereof;

FIG. 4 is a back elevational view thereof;

FIG. 5 is an enlarged bottom plan view thereof; and,

FIG. 6 is an enlarged top plan view thereof.

The three small squares on the end of the clip and the crisscross pattern on the grip in broken lines are shown for environmental and illustrative purposes only and form no part of the claimed design. 

The ornamental design for a writing instrument, as shown and described. 